Key blank identification system with groove scanning

ABSTRACT

A key identification system is provided. The key identification system comprises an imaging system to capture an image of a master key, and a logic to analyze the captured image. The imaging system may be capture an image of a groove in the master key from an angle between perpendicular and parallel to the blade of said master key. The logic analyzes the captured image to compare characteristics of the groove with groove characteristics of known key blanks to determine the likelihood of a match between the master key and a known key blank. The key identification system may further compensate for displacement or orientation of the master key with respect to the imaging system when analyzing characteristics of the groove.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/351,634 filed on Nov. 15, 2016 entitled “KEY BLANK IDENTIFICATIONSYSTEM WITH GROOVE SCANNING,” which is a continuation of U.S.application Ser. No. 14/162,157 filed on Jan. 23, 2014 entitled “KEYBLANK IDENTIFICATION SYSTEM WITH GROOVE SCANNING,” which is acontinuation of U.S. application Ser. No. 12/772,709 filed on May 3,2010 entitled “KEY BLANK IDENTIFICATION SYSTEM WITH GROOVE SCANNING,”which claims the benefit of priority of U.S. Provisional PatentApplication Ser. No. 61/215,152 filed on May 1, 2009, and U.S.Provisional Patent Application Ser. No. 61/275,654 filed on Sep. 1,2009, each of which are hereby incorporated by reference in theirentirety.

FIELD OF ART

This invention relates generally to the field of systems for identifyingobjects and, more particularly to systems for utilizing electronic meansfor identifying key blanks that are compatible with an unknown key.

BACKGROUND OF THE INVENTION

The art of key replication is well known. Commonly, a key intended forduplication (the master key) is copied on to an appropriately identifiedkey blank utilizing any number of different systems known in the art.The process of identifying an appropriate key blank to use when makingcopies of a key can be a difficult, tedious and time consuming affair.It is important that each master key be copied onto the proper key blankso as to prevent numerous adverse consequences caused by reproducing amaster key onto an inappropriate key blank. However, choosing thecorrect key blank can be difficult even for experts in the field.

There are hundreds, if not thousands, of key blanks, and many blanks arenot readily distinguished from others. Identifying the correct key blankfor use in duplication involves selecting a blank from hundreds or eventhousands of possibilities, where differences between key blanks may bevery subtle. These hard-to-notice subtleties significantly increase thelevel of difficulty for all operators of such key replication systems,both inexperienced trainees and experts alike.

Once a key blank is chosen, it goes through a cutting process. Thetypical cutting process simply traces the profile of the master key ontothe key blank, such that the key blank will exactly match (within theerror limits and accuracy of the tracing machine) the original masterkey. Normally, a mechanically linked cutting wheel actually cuts intothe key blank while it mimics the movement of the tracer as the tracermoves longitudinally along the profile of the master key. If theincorrect key blank is provided during this process, the key blank beingformed into the duplicate key may not possess the correct longitudinallength, thereby causing a failure. When this type of failure occurs, theentire process of selecting a key blank for replication and thenmechanically cutting the key must begin again. Worse still, if the blankhas the proper length but does not possess the appropriate thickness,contour, groove or other traits, the failure may not be discovered untilthe key is actually inserted into the lock.

Businesses that offer key cutting services are often times not staffedby experienced locksmiths. Instead, employees are usually trained to“eyeball” what is thought to be the correct blank and then cut aduplicate key. Such informal and imprecise key blank identificationinvariably increases the rate of failures for the duplication process.These failures often occur at the expense of the industry and to theextreme dismay of the key holder. Therefore, the industry would welcomean easy-to-use key blank identification system that increases theaccuracy and efficiency of key replication.

Not surprisingly, numerous attempts have been made to improveidentification systems and/or key replication systems. Many of theseimprovements include imaging systems designed to determine the properkey blank based on physical parameters of the key to be copied, such aslength, shape, and groove characteristics.

While many of these systems provide useful improvements for determininga proper key blank, they still suffer from various deficiencies.Specifically, many of these systems compare scanned data from a masterkey to be copied with data from known key blanks in order to determineif the master key matches the key blank. However, in some instances thescanned key parameters and the key blank data are insufficient todetermine a matching key blank. In such cases, additional informationabout the master key and the key blank would be useful in narrowing thefield of prospective key blanks. Accordingly, an improved system andmethod for determining a key blank is needed.

SUMMARY

A key identification system is provided. The key identification systemcomprises an imaging system to capture an image of a master key, and alogic to analyze the image. The imaging system may be configured tocapture an image of a groove in the key from an angle betweenperpendicular and parallel to the blade of said master key. The logicanalyzes the captured image to compare characteristics of the groovewith groove characteristics of known key blanks.

The key identification system may account for the orientation orpositioning of the master key with respect to the imaging system or keyholder to determine groove characteristics of the master key. Forexample, the logic may analyze a contour of the groove and determinegroove characteristics of the master key based on the contour and theorientation and positioning of the master key.

DESCRIPTION OF THE DRAWINGS

Objects and advantages together with the operation of the invention maybe better understood by reference to the following detailed descriptiontaken in connection with the following illustrations, wherein:

FIG. 1 illustrates a master key;

FIG. 2a illustrates a first example configuration of a key ID system;

FIG. 2b illustrates a second example configuration of a key ID system;

FIG. 3 illustrates an example silhouette of a key tip;

FIG. 4 illustrates an example configuration of a key ID system withreflectors;

FIG. 5 illustrates an example scanned image of a master key bladesilhouette;

FIG. 6 illustrates an example projection of a tip outline onto the imageof a tip;

FIG. 7 illustrates an example calculated data set of tip groovecontours;

FIG. 8 illustrates an example matching comparison between master key tipcontour data and stored key blank data; and

FIG. 9 illustrates an example unmatched comparison between master keytip contour data and stored key blank data.

FIG. 10 illustrates the coordinate references for the outline cameraimage.

FIG. 11 illustrates the coordinate references for the outline cameraimage including the outline vanishing point.

FIG. 12 illustrates the coordinate references for the groove cameraimage including the groove vanishing point relating to the y-axisprojection.

FIG. 13 illustrates the coordinate references for the groove cameraimage including the groove vanishing point relating to the x-axisprojection.

FIG. 14 illustrates an angular coordinate system for a master key.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to exemplary embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. It is to be understood that other embodiments may be utilizedand structural and functional changes may be made without departing fromthe respective scope of the present invention.

A system and method for identifying a key blank are provided. The system(“key ID system”) analyzes a master key to be duplicated, such as ahouse key, car key or other key, and determines the appropriate keyblank to be used in duplicating the master key. The system and methoddescribed herein may be used independently to determine a proper keyblank, or may be used in conjunction with other systems to narrow thefield of prospective key blanks. Moreover, it will be understood thatexisting key identification systems may be modified or retrofitted toimplement some or all features described herein.

The key ID system may scan a master key to determine traits andcharacteristics of the master key. Based on these characteristics, thekey ID system may then determine the proper key blank to be used toduplicate the master key. The key ID system may include any means knownin the art for determining the traits and characteristics of the masterkey geometry. For example, the key ID system may include an imagingsystem, such as a camera, laser, or any other imaging system known inthe art. The imaging system may scan the master key to determinecharacteristics of the master key, specifically characteristics that maybe unique to a specific key blank. While the key ID system is describedherein as including an imaging system, it will be appreciated that otherknown methods or devices, such as electrical or mechanical sensors, maybe used in place of or in conjunction with the imaging system todetermine the traits and characteristics of the master key geometry.

With reference to FIG. 1, a master key 10 is depicted. The master key 10may include standard key features such as a head 16 connected to a blade18 and a groove 11. The groove 11 may comprise a channel, opening,geometric shape, or other indentation formed in the blade 18. A masterkey 10 may include a single groove 11 on one side of the blade 18, asingle groove 11 on each side of the blade 18, multiple grooves 11 oneither side of the blade 18, or any other configuration of grooves 11with respect to the blade 18. Further, it will be appreciated, that themaster key 10 may be any key and is not limited to keys having a head16, blade 18 or groove 11.

The key ID system may include a key holder to hold the master key. Thekey holder may be any device capable of holding or supporting a masterkey. For example, as shown in FIGS. 2a and 2b , the key holder 13 maycomprise a lower support 15 and an upper door 12 to close onto the key.The key holder may alternatively comprise a clamp, gripper, platform,suspension, or any other device configured to hold the master key 10.

In an embodiment, the key ID system includes a camera system. The camerasystem includes one or more cameras configured to record images, such asdigital images, of the master key. The camera system may further includeother components to assist in recording images of the master key, suchas lights and mirrors. The lights may be positioned to enhance theclarity and quality of the image recorded by the camera. The mirrors maybe positioned to allow a camera in a first position to record an imageof the key from a second position. The mirrors may further allow asingle camera to record multiple images of the master key from differentangles, thereby increasing the amount of information related to themaster key recorded by a single camera.

The key ID system may include a logic to analyze images captured by theimaging system. As used herein, the term “logic” includes but is notlimited to a software, a firmware, an executable program, a hardware orhard-wired circuit, or combinations thereof. For example, based on adesired application or needs, a logic may include a software controlledmicroprocessor, discrete logic like an application specific integratedcircuit (ASIC), an analog circuit, a digital circuit, a programmed logicdevice, a memory device containing instructions, or the like. Logic mayinclude one or more gates, combinations of gates, or other circuitcomponents. Logic may also be fully embodied as software. Where multiplelogical logics are described, it may be possible to incorporate themultiple logical logics into one physical logic. Similarly, where asingle logical logic is described, it may be possible to distribute thatsingle logical logic between multiple physical logics.

The logic may be configured to determine a correlation or likelihood ofa match between a known key blank and the master key. For example, thelogic may include a database to store key related information (“keydata”). The key data may include characteristics of known key blanks,such as length, shape, bitting information, size, shape and location ofkey grooves, and other geometric and physical characteristics of knownkey blanks. The database may be integral with the logic, incommunication with the logic, or remotely accessible to the logic. Thedatabase may associate key data with specific key blanks or with typesor groups of key blanks. For example, the database may associate keydata with specific key manufacturers or different types of keys such ashouse keys or car keys. The key ID system may access the database tocompare scanned characteristics of the master key with the stored keydata in the database. Key blanks that do not have characteristicsconsistent with those of the master key may be then ruled out aspossible matches for the key blank. The key ID system may scan themaster key 10 one or more angles and compare the scanned data withstored key data.

The key ID system may scan a master key 10 to determine informationrelated to the groove 11. Keys and key blanks commonly include a groove11 or grooves 11 in the blade 18 of the key. Characteristics of thegrooves 11 may be unique to a given key blank or group of key blanks.For example, the size, location, angle, and other geometric parametersof a given groove may be unique to a key blank or blanks. Further, thelocation of a groove 11 on a first side of the key blade (“top groove”)may be unique with respect to the location of a groove 11 on the secondside of a key blade (“bottom groove”).

The key ID system may analyze various aspects of the groove 11 of amaster key 10. For example, the imaging system may capture an image ofthe groove 11 from a position perpendicular to the key blade 18, asillustrated by the overhead camera 20 in FIG. 2a . This camera angleprovides a top view of the blade 18 and allows the overhead camera toscan the length of the groove 11. The imaging system may also capture animage of the groove 11 from the end of the tip 14 at an angle parallelto the blade 18. This angle provides a view of the groove 11cross-section. However, neither overhead scanning of the groove 11 norparallel scanning of the groove 11 provide sufficient contrast betweenthe groove 11 and the rest of the key 10 to effectively determinecertain parameters of the groove 11.

In many keys, a groove 11 extends from the shoulder 16 through the tip14 of the key 10. Therefore, the shape and contours of the tip geometryreflect characteristics of the groove 11. Accordingly, uniquecharacteristics of a master key may be determined by scanning the tip 14from an angle designed to capture the top groove or bottom groovecharacteristics. This may be best accomplished by scanning the tip 14 atan angle other than perpendicular or parallel to the blade 18. Forexample, as shown in FIG. 2a , the key ID system may include a camera 22facing the tip 14, and positioned at an angle slightly above parallel tothe blade. In an embodiment, the camera is positioned facing the tip ofthe key 10, between 5 and 15 degrees from parallel to the blade of thekey 10. This positioning allows the camera 22 to capture the contours ofthe tip 14 formed by the bottom groove 11. Alternatively, it will beappreciated that the camera may be positioned similarly underneath thekey to capture the contours of the tip 14 formed by the top groove 11.As illustrated in FIG. 3, the camera 22 may capture a silhouette of thebottom groove. This silhouette may be unique to a key blank or group ofkey blanks, thereby narrowing the field of prospective key blanks.

It will be appreciated that configurations other than the cameraconfiguration shown in FIG. 2a may be used to capture the tip-groovegeometry. For example, the key ID system may include only a groovecamera 22 without any overhead camera 20. Further, the key ID system mayinclude a plurality of mirrors to allow a single camera at a remoteposition to capture multiple angles of the master key, including anglesof the tip 14. In an embodiment, as shown in FIG. 4, a first mirror 30may be positioned to provide a top view of the tip 14 from behind thekey 10. A mirror may be similarly positioned below and behind the key 10to capture an image of the bottom groove 11. This view allows the camerato capture the contours of the tip 14 formed by the top groove 11. Asecond mirror 32 may also be positioned to provide a top view of the tip14 from in front of the key 10. This view allows the camera to capturethe contours of the tip 14 formed by the bottom groove 11. It will beappreciated that the key ID system may include any number of cameras,mirrors, and other imaging devices to capture the desired views of thecontours of the tip 14. In an embodiment, the key ID system scans themaster key 10 to capture the silhouette of the blade 18, as shown inFIG. 5. This silhouette is used to determine the outline shape of thetip 14 in order to isolate groove geometry from the tip geometry. Thekey ID system may also scan the tip 14 from an angled position tocapture the contours of the tip 14 formed by the groove 11.

As shown in FIG. 6, a trigonomic projection of the tip 14 may be used toidentify the portion of the tip contour that is due to the groove shape.Specifically, contour data related to contours of the groove 11 may bedetermined by calculating a set of scalar variables based on imageinformation and machine constants. As described herein, points in theimage taken by the overhead camera 20 are mapped to their correspondingpoints from the image taken from the groove camera 22.

The contour image may be compiled from data obtained by the overhead oroutline camera 20. Once the outline or contour data has been generated,the outline image is rescanned to generate a set of data points, asshown in FIGS. 7-9. For example, data points may be generated every0.005 inches along the tip of the key. The data point interval of therescanned or resampled image may be adjusted based on the requiredaccuracy for groove identification and the optical characteristics ofthe outline and groove cameras. For example, the data point interval maybe 0.002 in order to obtain a better defined sample.

The groove contour may be compared to contours of known key blanksstored in the database to determine a matching key blank. Toleranceand/or correlation values may be set to determine if the comparisonyields a match. FIG. 8 illustrates a comparison between a scanned keytip contour and stored key data of a known key blank. The statisticalcorrelation value between the data sets is approximately 0.985,indicating a match between the master key and compared key blank. FIG. 9illustrates another comparison between a scanned key tip contour andstored key data of a known key blank. The statistical correlation valuebetween the data sets here is approximately 0.879, indicating that themaster key and compared key blank do not match.

Referring to FIG. 2a , the plane of the overhead camera 20 imageintersects the groove camera 22 image at the lower edge of the dooropening 12. The overhead camera 20 observes the profile of the key 10while the groove camera 22 is focused on the tip of the key 10. Withreference to FIGS. 10-13, the line at which these two images intersect,referred to as the door axis 52, is a primary axis for purposes ofdetermining contour data. The primary reference or origin point of thedoor axis is located at the center of the door 12. The plane of the dooralso passes through this intersection and is by definition perpendicularto the overhead camera 20 image plane.

A silhouette image of the key 10 may be captured by the groove camera22. To capture the silhouette image, the key ID system may utilizeelements such as a light source 24 and a diffuse reflector element 26,as shown in FIGS. 2a and 2b . The light source 24 may be shielded with alight shield 28 to illuminate the reflector element 26 while avoidingthe tip of the key 10. In an embodiment, the directional light from thelight source 24 is angled to direct the light substantially on thediffuse reflector element 26, but not on the tip of the key 10.

The light source 24 may be any light source known in the art. Forexample, the light source 24 may be a series of discrete LED lightssubstantially oriented in a row. It will be appreciated, however, thatthe light source 24 may be any lights arranged in any configuration. Thediffuse reflector element 26 may be affixed to the interior surface ofthe door, such that when the light from the light source 24 strikes thediffuse reflector element 26, the diffuse reflector element 26 providesa backlit area. In other words, this arrangement provides a backlit areabehind the key 10 with respect to the groove camera 22 while minimizingthe amount of light that is directed toward the key 10. Thus, the groovecamera 22 may view the key 10 tip as a substantially dark or blackfeature, similar to that shown in FIG. 3. It will be appreciated,however, that the key ID system may include any additional lights, suchas backlights, positioned throughout the system.

With reference to FIG. 2b , an alternative configuration for the key IDsystem is shown. The groove camera 22 may be mounted in a verticalcamera box 23. The vertical camera box 23 mounts the groove camera 22 atthe bottom directed upward toward a mirror 25 mounted at the other endof the vertical camera box 23. The mirror 25 is directed toward the key10 tip, such that the angle of incidence is nominally about 15 degrees.However, it will be appreciated that the angle of incidence upon the key10 of the image may be any angle, preferably between approximately 5degrees and approximately 45 degrees.

The key 10 is not constrained to a particular orientation or positionwhen held within the key holder 13. With reference to FIG. 14, the keymay be tilted or yawed in a plane perpendicular to the orientation ofthe outline camera 20; tipped up or down relative to the plane definedperpendicular to the door opening 12; and rotated around the axis of thekey blank it self (rolled) or combinations of any of the preceding aswell as variations caused by the overall length of the key blade 10 thatwould position the tip of the key at various focus positions relative tothe groove camera 22. Thus it is necessary to correct for the opticaldistortions and transform the images obtained from the two differentcameras to obtain an effective image of the tip 14.

The concept of a vanishing point is used to handle the foreshortening ofthe key 10 when viewed by the groove camera 22. The effects of thisforeshortening vary greatly as the end of the key 10 is tipped up ordown slightly by the clamping action of the door 12. The distance fromthe door to the vanishing point may be substantially affected by thistipping action.

To compensate for the angle between the groove camera 22 and the key 10,the distance from the tip of the key to the door axis is readilydetermined for both the overhead camera 20 image and groove camera 22image. The ratio of these distances (hereinafter “GrooveLR”) isdependent both on the angle between the groove camera 22 angle and thekey tipping angle. The actual values of these angles may be ignoredbecause only the ratio is required for the calculations to compensatefor the key location.

In an embodiment, a groove image vanishing point may be determined bymultiplying the distance to the outline image vanishing point by theratio GrooveLR. The outline image vanishing point may first beempirically determined. For example, previous test indicate a sampleoutline image vanishing point to be 20 inches from the origin of thedoor axis. The outline image vanishing point depends on theconfiguration of the key ID system and the characteristics of thecameras. Vanishing points may be assumed to be on the door centerlineaxis. However, in other embodiments vanishing points may be offset fromthe door centerline axis with additional compensation.

FIGS. 10-13 illustrate a crop box 50 used for limiting the image of thekey 10. An example of an outline crop box 50 is shown in FIG. 5, wherethe outline crop box 50 defines the outer periphery of the image. Theoutline crop box functions to limit the image that is actually processedby the system, even though the actual image captured by the camera islarger than the outline crop box 50. The outline vanishing point is farto the left of the outline crop box 50 along its X axis shown as point52. The groove vanishing point is above the groove crop box 60, shown inFIG. 6, along it Y axis at point 62. The groove crop box 60, serves asimilar function to the outline crop box 50, namely it reduces theoverall image processed by the system to a subset of the actual imagecaptured, in this case by the groove camera 22. This outline imagevanishing point distance is combined with vOutX to calculate the x axisdistance from the vanishing point to the starting point. While aspecific method determining the vanishing points and associateddistances is described, it will be appreciated that other methods may beused.

FIG. 10 shows the position of the starting location relative to the dooraxis and the Outline Camera image. vOutX and vOutY are the x and ycoordinates of a point at the tip of a key image that is to be mapped tothe groove image. These points correspond to the set of data points thatdefine the tip of the key. The units of the outline camera 20 are inpixels. Thus a series of vOutX and vOutY points are created to definethe tip of the key.

FIG. 11 shows the starting point translation to distances from theoutline view vanishing point. This distance is multiplied by GrooveLR toyield the outline VPy shown on FIG. 11 and referred to as GVPY (grooveimage vanishing point distance).

FIG. 12 shows the construction of the projected tip point y axiscoordinate. This projection is made on the Groove Camera image plane.The y axis projection is simply the difference between GVPY andGrooveVP.

The x axis projection calculation uses the GVPY to GrooveVP ratio asshown in FIG. 13. The Groove Door X distance may be determined from theoutline image. The Groove Door X distance may be scaled by the GVPY toGrooveVP ratio and added to the Groove Crop Box Center distance to findgsx which is the x axis coordinate. A trim value may be added to enablesmall physical offsets to be adjusted during machine calibration.

Once each point on the outline camera 20 image has been mapped to thegroove camera 22 image, the groove contour data may be determined. FIG.6 shows a typical groove image with two rows on points drawn at its tip.The row that is touching the tip may be calculated using the methoddescribed here. The lower row may be extrapolated from the same datapoints.

The groove contour is found by measuring the distance from a point thatis eight pixels below the mapped point to the actual white to black edgein the groove image. Giving the edge detection software the extra pixelsallows it to readily find a transition and allows for small errors ifthe mapped points are slightly above the actual transition. The set ofthese distances forms the groove contour.

Various tip shapes and bittings near the tip of the key may affect theimage of the grooves as seen by the groove camera 22. Therefore, it maybe helpful to manipulate the groove data in an attempt to compute howthe grooves would appear if the key blade was cut off square. Toaccommodate this manipulation, a scan of the outline data (from theoutline camera 20 image) along the tip of the key may be performed withrespect to a series lines that are parallel with the axis of the key.This yields a series of measurements that determine the distance fromthe edges of the tip of the key to some arbitrary squarely cut edge.These measurements may then be translated to the groove camera 22 imageusing a process described below. These translated key tip points 62 inthe groove image 60 represent the tip of the key as if there were nogrooves in the key. Differences between these points and the observededge of the tip of the key in the groove image 60 represent the actualshape of the grooves as if the key blade was cut off square.

The final task of blank identification is to match the measured contourwith the stored characteristics. The type of key 10 may be used to helpmatch the contour with the appropriate data set. For symmetrical doublesided keys the direction of the key insertion into the keyidentification system is irrelevant because the grooves and otherfeatures are symmetrical so a single characteristic reference image isstored for those symmetric keys. For most single sided keys, both sidesof the key (referred to as left and right) are distinctive. In thosecases, the characteristic reference images for each key includes a leftand right view. When performing comparisons, right cuts are only matchedto data for single cut blanks and only right cut data for those blanks.The data is also aligned so the key reference sides (e.g. in the case ofa single sided key, the flat of the blank) are near each other. Oftencut key data has many fewer data points so it is assumed data pointsopposite the reference side is where the metal (and data) have beenremoved. Double cut keys are matched based on the centerlines.

A series of comparisons may performed between the characteristicreference image that is stored in the database and the actual capturedimage to compensate for small registration errors. The comparison may beperformed via a 2-D correlation analysis described in greater detailbelow. Specifically, the data may be moved a few data points in eachdirection. These points may then be compared and analyzed with the bestresult being chosen as the correct data point.

Small errors in image registration and performing the transpositionsbetween the images can cause the contour data to be sloped up or down.This is called “roll” and is similar to an airplane roll where the wingsare not level. Some level of roll is presumed to be dependent on uniquemachine set up details. To compensate for this roll, each key ID systemmay have a roll constant that is used to adjust its measured values.This insures that biases are not a factor when compared to stored datasets that were generated on other machines.

There also may be roll based on individual key scans. A second roll testmay be used to insure the best possible match after the machine roll hasbeen accounted for, and the best horizontal sliding position has beendetermined. Each comparison is done for as many as 40 different rollvalues to determine the best match. These calculations assure thecomparison is done as accurately as possible. In other embodiments,larger numbers of roll values may be used to handle greater variation inthe image captured by the groove camera 22.

Mathematical correlation may also be as the basis of contour comparison.The correlation may be done based on a standard formula. However, if adata point in the newly collected data or stored data is potentially inerror it may be excluded from the correlation calculation. The actualdata may have values larger than one as we begin the scan for grooveedge data 8 pixels below the first expected transition point.Alternatively, different pixel offsets may be used based on thelikelihood of erroneous data. If this data is set to −1 that point isexcluded from the calculation. Some stored data is manually set to −1 tocompensate for scan errors and to de-emphasize some features of thecontours. Errors in edge detection can cause −1 values in the newlyscanned data.

Other methods may be employed to compare the tip image to the referencecontours. One method is to fit the contour inside an envelope based onthe stored contours. Other techniques taking advantage of various basisfunctions are also suitable for performing the comparisons between thecharacteristic reference images and the captured image in order toobtain a match as well.

A secondary test may be added to the standard correlation calculation.Some key blanks have the same overall pattern of grooves, but the groovedepths are exaggerated on some blanks more than others. Sincecorrelation may be insensitive to scale, these blanks may be found tomatch even where there are large differences in actual groove depths. Asecond factor based on the standard deviation of the two contour datasets is used to aid in this differentiation. The factor is calculated bytaking the difference between the two standard deviations and dividingit by the sum of the two values. This value is then subtracted from thecorrelation coefficient and a secondary test is performed. The resultingcorrelation results are used to provide an estimate as to which type ofkey is inserted into the key ID system. In an embodiment, thecorrelation results are used in conjunction with the key outlinecharacterization to further narrow and reduce the type of keyidentified.

Both the standard correlation value and the adjusted correlation valueare unitless and non-scaled numbers between 0 and 1. In order to providemore meaning to the values, each is rescaled to a scoring system of 0 to100% where 0 is considered to be an impossible match and 100 is aperfect match. In an embodiment, standard correlations of 0.60 to 1.0are rescaled to a score of 0 to 100% and adjusted correlations of 0.50to 1.0 are rescaled to a score of 0 to 100%. Any correlations of lessthan the 0.60 and/or 0.50, respectively, are considered to be impossiblematches. The total groove scanning score or correlation score may be aweighted average of these two individual scores.

The key ID system as described may be used in conjunction with otherknown key identification systems. For example, the key ID system may beused in conjunction with user interface identification systems, such asthe object identification system disclosed in U.S. Publication No.2004/0095380 and the key duplication system disclosed in U.S.Publication No. 2007/0224008, each of which are hereby incorporated byreference in their entirety.

The invention has been described above and, obviously, modifications andalternations will occur to others upon a reading and understanding ofthis specification. The claims as follows are intended to include allmodifications and alterations insofar as they come within the scope ofthe claims or the equivalent thereof.

What is claimed is:
 1. A key identification system comprising: animaging system including a camera configured to capture an image of amaster key, wherein said image includes a contour; a reflecting devicepositioned in alignment with said camera for capturing said image; alogic configured to analyze said captured image to determinecharacteristics of said contour and compare said characteristics withcharacteristics of known key blanks to determine the likelihood of amatch between said master key and a known key blank; and wherein saidlogic accounts for positional variations of said master key with respectto said imaging system to determine characteristics of said contour. 2.The key identification system of claim 1, wherein said logic includes adatabase containing data related to characteristics of grooves of knownkey blanks.
 3. The key identification system of claim 1, wherein saidimaging system includes a light.
 4. The key identification system ofclaim 3, wherein said light is directed toward said reflecting device.5. The key identification system of claim 4, wherein said light includesa shield to direct light away from said master key.
 6. The keyidentification system of claim 1, wherein said captured image is adigital image.
 7. The key identification system of claim 1, wherein saidcaptured image comprises a silhouette of said tip of said master key. 8.The key identification system of claim 1, wherein said positionalvariations include rolling of said master key with respect to saidimaging system to determine characteristics of said contour.
 9. The keyidentification system of claim 1, wherein said positional variationsinclude tilting of said master key with respect to said imaging systemto determine characteristics of said contour.
 10. The key identificationsystem of claim 1, wherein said positional variations include tipping ofsaid master key with respect to said imaging system to determinecharacteristics of said contour.
 11. The key identification system ofclaim 1 wherein said captured image comprises a silhouette of the bladeof said master key.
 12. The key identification system of claim 1,wherein said characteristics of said contour are determined based onimage data from at least said two or more views of said master key. 13.The key identification system of claim 12, wherein said logic calculatesthe geometry of the contour as seen from a view of the tip parallel tothe blade based on data from at least said two or more views of saidmaster key.
 14. The key identification system of claim 12, wherein saidlogic calculates the geometry of the contour as though the tip weresquarely cut based on data from at least said two or more views of saidmaster key.
 15. The key identification system of claim 1 furthercomprising a key holder configured to hold said master key.
 16. The keyidentification system of claim 15, wherein said key holder includes aclamp.
 17. The key identification system of claim 1, wherein one of saidviews of said master key includes a view from above the master key bladeof a groove in the bottom of said blade.
 18. The key identificationsystem of claim 1, wherein one of said views of said master key includesa view from an angle between perpendicular and parallel to the blade ofsaid master key and not including perpendicular or parallel to the bladeof said master key.
 19. The key identification system of claim 1,wherein the logic is configured to shift data related to saidcharacteristics of said contour to compare with said known key blankcharacteristics.
 20. The key identification system of claim 1, whereinsaid logic includes a tolerance range for each characteristic of saidmaster key to determine whether a master key passes or fails to match aknown key blank.